The House of Munsö (Swedish: Munsöätten), also called the House of Björn Ironside (Swedish: Björn Järnsidas ätt), the House of Uppsala (Swedish: Uppsalaätten) or simply the Old dynasty (Swedish: Gamla kungaätten), is the earliest reliably attested royal dynasty of Sweden, ruling during the Viking Age. None of the names suggested for the dynasty are universally accepted and most are problematic; the name "House of Munsö" derives from a questionable and speculative theory that they would have ruled from the island of Munsö and the name "House of Björn Ironside" derives from the supposed founder of the dynasty, Björn Ironside, who is often seen as a legendary, rather than historical, figure.
A long and elaborate sequence of kings of the Munsö dynasty can be found in 12th and 13th century Icelandic sagas, but the sagas are overwhelmingly considered unreliable, with the kings that appear in them seen as legendary figures. The sequence of kings in the sagas is contradicted by more contemporary German sources such as the 9th century writings of Rimbert and the 11th century work of Adam of Bremen.